1. Field of the invention
The present invention relates to an improved bone plate structure and more particularly, an approximately π-shaped improved bone plate structure.
2. Description of the prior art
Since the knee is one of the most important joints for bearing weight, the condition thereof affects the flexibility of action so as to relate to all activities required in daily life.
The symptom of degenerative arthritis of the knee generally comprises knee pain, knee weakness and lack of popliteal flexibility. Moreover, while the symptoms aggravate, pain occur on the proximal tibial articular surface of the knee, and may possibly causes the back pain, calf pain or ankle pain jointly. Meanwhile, the articular cartilage of medial knee gradually deteriorates to forms a varus knee due to the heavier loads at the medial condyle. Therefore, it is almost impossible for the sufferer to squat or to walk for a long time normally so as to seriously affect the quality of life of the sufferer.
However, with the development of medicine science, several treatments for curing the degenerative arthritis have been discovered recently. The treatments can be generally divided into two different aspects of medical treatment and surgical treatment. More specially, the surgical treatment may further comprises the treatment of total knee replacement and high tibial osteotomy.
Furthermore, the full artificial knee joint replacement treatment shall not be firstly considered since the artificial knee joint has plurality of disadvantages of expensive, relatively short service life, relatively high risk of infections and high difficulty and cost of treatment thereof unless the gonarthritis has already spread to the entire surface of the articular, or the gonarthritis is too serious for medicine treatment, or the knee pain of the sufferer cannot be retard consistently. Furthermore, after the full artificial knee joint replacement treatment, the sufferer shall no longer able to take the high strength sport such as running or mountaineering. Meanwhile, the allowable rotating angle of the knee is limited.
Therefore, instead of the full artificial knee joint replacement treatment, the treatment of high tibial osteotomy is preferred if the gonarthritis of the knee is only limited to only part of the proximal tibial articular surface.
A high tibial osteotomy looks to realign the knee to evenly share weight between both the inside and outside of the knee. This is achieved by cutting the bone and then taking a wedge of bone out at about two centimeters away from the tibial articular end, forming a filling portion thereon and adding a wedge of bone therein.
This high tibial osteotomy surgery has a long recovery period as the cut essentially fractures the main weight bearing bone of the lower leg. Even after surgically fixing the bone in its new position, it is unable to take any weight for a significant period of time. This has a major implication for work, lifestyle and everyday activities.
Accordingly, a bone plate structure is required to reinforce the bone after the surgery so as to share the weight of the sufferer in order to avoid the fracture of the tibial. Traditionally, the bone plates are T shaped, I shaped or L shaped which is only capable of covering a small and very limited portion of the proximal tibial articular surface. Please refer to the FIG. 1, FIG. 1 depicted a schematic figure of an I-shaped bone plate of a prior art. In the Taiwan patent publication No. 200800094, the reference discloses an I-shaped bone plate having a small head portion which is utilized to be fixed on the proximal tibial articular surface. Since the surface area of head portion of the bone plate becomes very limited, the bone plate is relatively difficult to be fixed on the surface previously described and the bone plate may has loosing and shaking problem. Moreover, the bone plate structure may deform because of the stress concentration, damaging the bone plate inside of the body of the sufferer and hurting the sufferer. Furthermore, the traditional bone plate design covers the filling portion, retarding the user to observe or to process any treatment to the wound of the said opening filling portion via the tradition bone plate.
Therefore, a need exists to develop a bone plate which is capable of fitting the bone with multi-axis, decreasing stress concentration, preventing the opening filling portion from being unsuitably covered and preventing the wound deformation from being pressed by minimum cost.